Crystalline structurants are often used in liquid cleaning compositions as stabilizing and thickening agents, or in other words as structuring agents. Such systems are described in EP1328616A1. When added to a liquid composition, such as a liquid cleaning composition, these structuring agents provide a chemical network that reduces the tendency of the compositional components to coalesce and/or phase split. Hence, the structuring agents provide the liquid compositions with desired viscosity and improved shelf stability.
Often the crystalline structurants are derived from hydrogenated castor oils. The process of making the crystalline structurant comprises the steps of making an oil-in-water emulsion of the hydrogenated castor oil at elevated temperatures, and then cooling this to produce a final crystalline structurant. This final crystalline structurant is then added to the liquid cleaning composition in an amount needed to achieve a desired viscosity of the liquid cleaning composition.
However there remains considerable variability in the amount of the crystalline structurant that needs to be added to identical samples of the liquid cleaning composition in order to achieve consistent viscosity between the samples. Such variation is evident even when aliquots from a single sample of crystalline structurant are added to aliquots of a single sample of the liquid cleaning composition (i.e. the aliquots of structurant are identical and the aliquots of liquid cleaning composition are identical).
Such variability means that constant readjustment and amendment of the manufacture process is required. This is inconvenient, time consuming and costly.
Thus, there is a need in the art for a crystalline structurant that exhibits reduced variability in the quantity needed to be added to liquid cleaning compositions to achieve the desired rheological characteristics. There is also a need in the art for a convenient process to make such a crystalline structurant.
It was surprisingly found that the oil-in-water emulsions and process of the present invention achieved this.